The present invention relates generally to a thermoplastic web of film. More specifically, the present invention relates to a web of film, having a gas barrier, that can be utilized to make flexible containers.
Thermoplastic webs of film can be utilized to create flexible containers for housing products. These flexible containers are utilized, among other areas, in the medical industry for containing, inter alia, parenteral solutions such as intravenous solutions, dialysis solutions, frozen drugs, nutrition products, respiratory therapy products, and plasma. When these containers are utilized in the medical industry, because they will contain fluids or solids that are introduced into a patient's body, it is necessary for the containers to be: essentially transparent; flexible; essentially free of extractables; and capable of maintaining a product contained therein under sterile conditions until the product is accessed or removed from the flexible containers. The film from which these containers are constructed must also meet these requirements.
It is also important that the film used in constructing these containers is sufficiently strong so that the containers constructed from the film have sufficient strength. Furthermore, it is desirable, for economic reasons, that any such film be readily constructed into a flexible container on commercially available, or easily modified, production machinery.
As set forth above, because the web of film will be processed into a flexible container that houses a medical product that is introduced into a patient's body, it is necessary that the film structure does not contain chemicals that can be extracted by the medical product or are likely to pass with the medical product into the patient's body. This is especially critical with respect to the plasticizers utilized for making the web of film flexible. In this regard, it has been known to utilize polyvinyl chloride to make flexible containers. In order to make polyvinyl chloride sufficiently flexible, plasticizers have been added thereto. The toxicity of the plasticizers has been increasingly a matter of concern. Typically, diethylhexylphthalate (DEHP) and/or epoxidized oils are utilized as plasticizers for polyvinyl chloride. However, DEHP has become a suspect compound in that there is continued testing to determine if DEHP is a health hazard.
A further consideration in choosing a proper film for creating a flexible container is the product to be housed. In applications of the film to produce containers for products stored at ambient temperatures, it is desirable that the film provides a container with sufficient barrier properties. Without a sufficient barrier, water vapor, oxygen, and other gases and vapors may permeate the film deactivating or degrading the product contained therein. A web of film having a gas barrier for making flexible containers is disclosed in U.S. Pat. No. 4,692,361.